Ah. Looks like we may be getting somewhere. Seems like your 6-8 hours of sleep may be more like a 1.5 hour nap followed by a 1 hour nap followed by a 1.5 hour nap followed by another 1.5 hour nap, etc. You're probably not getting any of that good healing delta wave sleep so, yes, it makes pefect sense that your T level is in the mid 100's.
Do you wake to empty your bladder or do you go to the bathroom anyway since you're up? Whether you wake to empty your bladder or not, you may want to measure yourself on the Epworth Sleepiness Scale. You could have a case of sleep apnea. My pulmonary doctor explained it best. She said that each you stop breathing in your sleep you get a small drop in your blood oxygen level, which triggers your survival reflex which makes your adrenals squeeze out a little adrenalin to make you start breathing again. The problem is you also get a little rise in cortisol too. If you stop breathing several times per hour you're getting that many spikes in your cortisol. Those spikes could lead to a lowered testosterone level because cortisol is a T-killer. Cortisol also leads to increased visceral abdominal fat (not saying you have that), increased blood pressure and fluid retention. By not getting enough deep sleep, you can develop short term memory problems (mental fogginess), decreased focus, irritability and, again, low testosterone. Sounds like you should be reaching for a Midol any minute now, right? Anyway, supplementing with calcium a few hours before bed can help but use a calcium citrate not a calcium carbonate. That way there won't be a potential for interference if you take a ZMA supplement before bed.